Teaching adolescents effective coping skills can help them to manage stress, which is associated with health-risk behaviors including substance use and risky sexual behavior. Whereas stress reduction interventions commonly focus on reducing negative affect, there is a growing body of research that indicates that positive affect is beneficial in the context of stress. Drawing from our work (Folkman & Moskowitz, 2000) and the growing body of literature on predictors of positive affect under stress (Zautra et al., 2002, 2005), we developed a novel stress reduction intervention that has been successful in improving mood in high risk adult populations. The 5-session intervention teaches 8 skills (noticing positive events, capitalizing upon or savoring them, gratitude, mindfulness, positive reappraisal, personal strengths, attainable goals, and acts of kindness; Moskowitz, 2010; Moskowitz et al., under review). Using stress and coping theory (Lazarus & Folkman, 1984; Folkman, 1997), the broaden and build theory of positive affect (Fredrickson,1998), and the risk and protective factor framework (Hawkins, Catalano, & Miller, 1992) as our guide, we recently tailored the positive affect intervention to be delivered to adolescents as a school-based intervention: Coping and Emotional Development for Adolescents to Reduce Stress (CEDARS). In this study we propose a preliminary efficacy pilot trial of the CEDARS program in a sample of 60 students from a low resource, predominantly racial/ethnic minority public high school at high risk for engaging in risky health behaviors. The specific aims of the study are to: 1) investigate the preliminary effects of CEDARS on perceived stress, coping, and positive and negative affect; 2) determine preliminary evidence regarding whether CEDARS participation is related to reduced substance use, sexual risk behavior, and other health behaviors; and 3) determine whether affect and coping mediate the effect of the CEDARS intervention on health behaviors and attitudes. The proposed study will lay the groundwork to determine whether a more definitive R01-level randomized controlled trial to rigorously test the benefit of CEDARS as a school-based prevention program is warranted.